The present invention relates to liquid/gas mixers and more particularly concerns an aerator that is specifically arranged for projecting an aerated water jet into a spa, therapy pool, swimming pool, or the like.
In a common and widely used type of spa or therapy pool a recirculating water system is provided, including a return line for flowing heated water to the basin in which the spa water is confined. The desired and beneficial action of the spa is provided, or at least enhanced, by flowing air into the returning water so that a number of jets of aerated or bubble-filled water are provided at various points about the spa basin. Such an arrangement, employing a motorized blower for providing suitable source of air, is shown in a co-pending application of Lawrence E. Johnson, et al for Aerator, Ser. No. 606,299, filed Aug. 25, 1975. Such aspirators, or aerators as they are commonly termed, often employ a constricted water flow passage of the venturi type that provides a high velocity flow of water into a chamber which is supplied with air by means of an air conduit. A jet of water flows from the mixing chamber at relatively high velocity, entraining air from the chamber to thus provide an aerated water stream. U.S. Pat. Nos. 3,628,529, and 3,985,303 to W. D. Steimle, and U.S. Pat. No. 3,890,655 to Mathis, illustrate aerators of this configuration. Aerators of the type shown in the patents to Steimle and Mathis are relatively bulky and are difficult to install in restricted areas.
U.S. Pat. No. 3,890,656 to C. L. Mathis, shows a mixer in which connections for the water and air inputs are simplified. This patent employs air and water connections that may be coupled to suitable piping with relative ease in restricted areas, but nevertheless employs the widely used common mixing chamber into which both air and water are drawn from the air and water supplies for mixing and projection as an aerated jet.
Mixing arrangements of the prior art are relatively inefficient, often requiring pressurized air sources and higher water pumping power to obtain desired turbulence at the entrance of the aerated water jet into the body of water in the spa or therapy pool tub.
Where such spa or therapy pool systems are employed in commercial or public installations, such as in public spas or hotel baths, or the like, health codes require that maximum drainage of the connecting plumbing and the mixer heads themselves be provided to minimize the use of water retained from a previous use. The air/water mixing chambers of prior aerators, such as those of Steimle and Mathis, will trap residual water so that an undesired amount of water may remain in these mixers even after the bath or spa system has been otherwise fully drained. This may be unhealthy and may not meet codes.
Accordingly, it is an object of the present invention to provide a mixer that avoids or eliminates above-mentioned problems.